Papers finished by a copying machine or printer are temporarily stacked onto a tray unit for finishing processes such as stapling and booklet and then move to a paper stacker through a series of processes.
The papers stacked onto the paper stacker are aligned depending on contact with papers moved from the tray unit or distance between the paper stacker and the tray unit.
One example of a related art finishing apparatus in a copying machine is disclosed in the Japanese Patent Publication No. 4-316894.
A structure of a copying machine having a related art finishing apparatus will be described with reference to FIGS. 1 to 3.
FIG. 1 is a sectional view illustrating an outlet of a copying machine having a related art finishing apparatus. FIGS. 2a and 2b are sectional views illustrating the operation of the related art tray unit. FIG. 3 is a plane view of the related art tray unit.
A housing 15 of a related art finishing apparatus 12 is detachably provided in a copying machine 11. That is, the housing 15 of the finishing apparatus 12 can be detached from the copying machine 11 by a fixed portion 16.
The finishing apparatus 12 may be provided in the copying machine 11 to form a single body without being detached from the main body of the copying machine 11. The finishing apparatus 12 is connected with the copying machine 11 through a path network 18.
The path network 18 includes paper paths 20 and 21 having a roller 22 and a deflector 24.
The roller 22 and the deflector 24 are driven by a driving part 25. An outlet 28 is formed by the roller 22 and ejects papers through the paper path 20 or 21.
The paper paths 20 and 21 move the papers to an upper paper stacker 32 and a lower paper stacker, respectively.
At the outlet of the paper path 21, a rolling wheel 36 and a waveform roller 38 are provided along with the roller 22. The roller 22 has an arc shaped waveform to facilitate ejection of the papers at a proper speed. The rolling wheel 36 and the waveform roller 38 act to push the papers from the outlet.
The upper paper stacker 32 is fixed to the housing 15 while the lower paper stacker 34 is supported by an elevator assembly 44 and is linked to a side shift plate 45.
The paper stackers 32 and 34 are tilted to have a predetermined angle and allow a set of respective papers or stapled papers to be easily stacked thereon.
The elevator assembly 44 includes a truck 51, a cable 52 wound in a pair of pulleys 54, and an elevator support member 48.
The elevator support member 48 is slidably connected with the truck 51 and moves up and down in response to movement of the cable 52.
The pulley 54 is driven by an elevator motor 56, and the elevator motor 56 and the driving part 25 are programmably controlled by a controller 58.
Meanwhile, a tray base 10 is slidably fixed to a pair of support rails 62. The support rails 62 are fixed to both sides of the housing 15 but one support rail 62 is shown in a sectional structure of FIG. 1.
The tray base 10, as shown in FIG. 3, is formed of a rectangular shaped plate of metal or plastic, and a channel 69 is provided in a movement base in parallel with a moving direction of the papers.
The tray base 10 includes one or more paper contact plates 66 provided to form a single body with the corner of the tray unit, and a positioning unit having a side plate 68.
The positioning unit is provided with a jogging assembly 70. A wheel 2 connected with a shaft 73 is provided in the jogging assembly 70.
The wheel 72 is parallel with the surface of the tray base 10 and forms an acute angle with the plane of the side plate 68.
The shaft 73 is connected with a motor 74 which is connected with the controller, and the motor 74 drives the wheel 72.
Furthermore, when the stapled papers are input and output, a sensor 76 is provided below the tray base 10 to sense the height of the lower paper stacker 34.
The sensor 76 includes a paper clamp unit 77 and a switch 78. The switch 78 is connected with the controller 58.
The clamp unit 77 is bound into a predetermined arc and moves between the first part triggering the position of an open switch and the second part triggering the position of a closed switch.
Meanwhile, as shown in FIG. 1, the tray base is provided in such a manner that a reciprocating mechanism 80 elastically supported by a spring is connected with the finishing apparatus 12.
The reciprocating mechanism 80 is provided with a rotatable cam follower 82 which is connected to the rear of the tray base 10. The cam follower 82 is elastically supported by a spring 88 and is driven by a cam 90.
The cam 90 is fixed to a shaft 92 which is controlled by a motor 94. The motor 94 is connected with the controller 58.
The aforementioned reciprocating mechanism 80 can reciprocate the cam follower 82 and the tray base 10 when the cam 90 rotates along with the shaft 92 because the shaft 92 is eccentric with respect to the circumference of the cam 90.
The structure of the related art finishing apparatus will be described in more detail with reference to FIGS. 2a and 2b. 
A general stapler that staples papers is denoted by a reference numeral 96.
The stapler 96 is arranged to staple the corner of papers.
A base (anvil) having a sufficient area is provided so that a set of papers are not scattered during or before stapling operation when the papers are set between a core of the stapler 96 and the tray base 10.
The stapler 96 is provided at the rear of the tray base 10 and reciprocates along with the tray base 10.
Since the paper contact plate 66 is matched with and fitted into a channel 69, the paper contact plate 66 freely moves in the channel 69 when the tray base 10 is retracted.
The stapled papers can be extruded from the tray base 10 using a paper roller 100.
A driving gear 106 elastically supported by a spring is connected with the rear of the paper roller 100. The driving gear 106 has a structure similar to that of the reciprocating mechanism 80.
The driving gear 106 is provided with a cam follower 110. The cam follower 110 is elastically supported by a spring 112.
A cam 114 is fixed to the shaft 92 and reciprocates the cam follower 110 when the cam 90 reciprocates the cam follower 82.
The cams 90 and 114 are provided in such a manner that the front end of the tray base 10 is retracted to the front corner of the housing 15 or the end of the paper roller 100 moves to the front corner of the housing 15.
The operation of the aforementioned related art finishing apparatus will now be described.
Copying papers are fed to the deflector 24 arranged at a branch of the paper paths 20 and 21. If the papers are directly ejected without stapling operation, the deflector 24 conveys the papers to the upper moving path 20 using the driving part 25 and the controller 58. If the finishing process such as stapling is performed, the papers move to the lower moving path 21 using the driving part 25 and the controller 58.
If the printed papers are ejected from the end of the outlet of the lower paper path 21, the papers are arranged on both the lower paper stacker 34 and the tray base 10.
In other words, the first part of the papers is arranged on the lower paper stacker 34 while the second part is arranged on the tray base 10.
Since the paper stacker and the tray base are tilted at a predetermined angle, the second part of the papers arranged on the tray base is slid toward the rear of the tray base 10 by means of gravity and paper positioning is made in a moving direction of the papers by means of the paper contact plate 66.
At this time, the jogging wheel 72 rotates as the motor 74 is driven by a signal of the controller 58. The corners of the papers moved by the jogging operation of the wheel 72 are pushed to the corners defined by the paper contact plate 66 and the side plate 68.
Therefore, positioning of the papers is made in such a manner that the corners of the papers are perpendicular to the moving direction of the papers.
The waveform roller 38 and the rolling wheel 36 serve to control the speed of the papers when the papers are ejected from the paper path 21 and align the papers so as to prevent the papers from being scattered.
The positioned papers are stapled by the stapler 96 arranged at the corner.
Subsequently, the driving gear 106 operates as the motor 94 is driven through the controller, so that the paper roller 100 advances through the channel 69. The tray base 10 is retracted by the reciprocating mechanism 80 so that the stapled papers are ejected to the paper stacker 34.
If the paper roller 100 advances, the end of the paper roller 100 is in contact with the second part (lower part) of the stapled papers so as to push the contact part to the paper stacker 34 and at the same time move the tray base 10 and the papers in an opposite direction. Also, since the sensor 76 is retracted along with the tray base 10, the clamp unit 77 rotates from the first part to the second part, thereby moving the switch 78 to the open position.
When the corner at the rear of the stapled papers reaches the corner at the front of the housing 15, the papers are dropped onto the lower paper stacker 34.
Before the stapled papers are ejected from the tray base 10, the controller 58 transmits the signal received from the motor 94 to the elevator motor 56 and drops an elevator support member 48 by a predetermined distance.
The drop distance of the paper stacker is maintained within the range that the papers stacked onto the paper stacker 34 do not interfere drop of the next papers.
If the papers subjected to the finishing process such as stapling are ejected onto the paper stacker, the tray base 10 returns to the original position of FIG. 2a. 
Once the tray base 10 returns to the original position, the paper stacker 34 connected with the elevator support member 48 starts to ascend by means of action of the truck 51.
The paper stacker 34 is shifted to the side by action of the side shift plate 45 before ascending operation. That is, the paper stacker 34 is disposed in the side by the side shift plate so that the stapled papers are stacked onto the paper stacker in a zigzag pattern, thereby facilitating distribution and disposal of the papers.
If the paper stacker 34 continues to ascend, the upper part of the papers stacked onto the paper stacker 34 is in contact with the clamp unit 77. The clamp unit 77 is pushed upwardly to turn off the switch 78.
Once the switch 78 is turned off, the signal is transmitted to the controller 58. The controller 58 transmits the signal to the elevator motor 56 to stop movement of the elevator support member 48.
However, the aforementioned related art finishing apparatus has several problems.
The distance between the tray base 10 and the paper stacker 34 is uniformly maintained regardless of the movement of the tray base 10 to the paper stacker 34, i.e., the front end of the housing 15 or the rear end of the housing 15. In this case, it is difficult to facilitate the finishing process of large sized papers.
The problems of the related art finishing apparatus will be described in more detail with reference to FIGS. 4 and 5.
If the papers are ejected through the paper path in a state where the tray base 10 of the tray unit is completely extended to the paper stacker 34, the tray base 10 guides the papers to the paper contact plate 66.
As shown in FIG. 4, if small sized papers 13 are provided, the papers are guided to the paper contact plate 66 in a state where the first and second part A and B of the papers are stably supported by the tray base 10. However, if large sized papers 13 are provided as shown in FIG. 5, the first part A of the papers ejected through the paper path is arranged on the paper stacker 34 and the second part B of the papers is arranged on the tray base 10.
If the papers are arranged on the paper stacker and the tray base as shown in FIG. 5, in the structure of the related art tray unit, fold “C” of the papers occurs at the outer end of the tray base 10. Such fold prevents the papers from being smoothly slid to the paper contact plate 66.
The large sized papers may be slid to the paper contact plate without fold by increasing the extension length of the tray base 10. However, in this case, problems arise in that the volume of the apparatus increases and reciprocating time of the tray base increases, thereby reducing efficiency of the apparatus.
In other words, the related art finishing apparatus has problems in that the finishing process of various sized papers, especially large sized papers cannot be performed with the small volume of the apparatus.